Not yet medically reviewed, information on this site is in preparation and has not been verified by a medical reviewer.
Drug index / Psychedelic / 2C-B
Psychedelic

What is 2C-B (2CB)?

2-(4-bromo-2,5-dimethoxyphenyl)ethanamine

2C-B is a single synthetic phenethylamine first made by Alexander Shulgin, and it is not the same thing as the pink powder sold under its name. Schedule II of the 1971 UN Convention. We have confirmed a legal status for 2C-B in 200 jurisdictions; the international section below gives each one, including any where it is not listed. Of 470 samples sold as tusi and analysed in Spain, 2C-B was detected in 3.6%.

Overview

2C-B is 4-bromo-2,5-dimethoxyphenethylamine, a single defined compound (C10H14BrNO2, PubChem CID 98527) first synthesised by the chemist Alexander Shulgin in 1974. It belongs to the 2C family of substituted phenethylamines, which share a common backbone and differ at the 4-position.

The single most important fact about 2C-B is what it is not. The powder sold as “tusi” or “pink cocaine” borrows the name — tusi is a phonetic rendering of “2C” — and usually contains no 2C-B at all. Energy Control, the Spanish drug-checking service, analysed 470 samples sold as tusi between 2020 and 2024: ketamine was detected in 93.2% of them and MDMA in 92.1%. 2C-B was detected in 3.6%. Those figures were reported by Abukahok, Fitzgerald and Palamar in Current Addiction Reports (2025).

So two different things share one name: a specific molecule, and a pink-dyed mixture named after it. A page, a law, a lab result or a news report may mean either. Keeping them apart is the whole point of this site, and conflating them is the most common error made about both.

The compound was sold openly in some countries in the 1980s and early 1990s under trade names before international control, which is why older references sometimes describe a legal status that no longer exists anywhere.

Source: PubChem CID 98527; Abukahok N, Fitzgerald ND, Palamar JJ, Current Addiction Reports 2025;12:90, doi:10.1007/s40429-025-00706-y

Chemistry & mechanism of action

2C-B acts principally at serotonin receptors, and its psychedelic effects are attributed to partial agonism at the 5-HT2A receptor — the same receptor that mediates the effects of LSD, psilocybin and mescaline. It also has affinity for 5-HT2C, and a weaker interaction with adrenergic systems is the usual explanation given for its stimulant-like component at lower doses.

Its pharmacology is unusually dose-dependent, and that matters more for 2C-B than for most psychedelics. The character of the effect changes with dose rather than merely intensifying: a smaller amount is commonly described as predominantly stimulant and body-loaded with mild visual change, and a larger amount as fully psychedelic. The interval between those two is narrow compared with classic psychedelics, which is the pharmacological reason small differences in an unmeasured street dose produce very different experiences.

Because it is a partial rather than full agonist at 5-HT2A, the dose-response does not scale indefinitely, and cross-tolerance with other classic psychedelics is reported.

Source: PubChem CID 98527; DEA drug fact sheet; EUDA

Effects

Public-health sources describe 2C-B as a hallucinogen with both stimulant-like and psychedelic effects that are strongly dose-dependent. Reported effects include visual distortion and colour enhancement, altered perception of time, emotional intensity, body-load, and stimulation. Nausea, anxiety, confusion, raised heart rate and raised blood pressure are commonly reported adverse effects.

Onset is typically slower than a snorted stimulant and the total duration is usually reported as several hours, shorter than LSD and closer to mescaline in character. The delayed onset is itself a documented hazard: it is the interval in which someone who feels nothing takes more, and because the dose-response is steep, redosing during onset is how a moderate dose becomes a heavy one.

Specific dose figures are deliberately not published on this page. This site does not publish dosing until it has been medically reviewed, and a dose range for a compound with a narrow window, printed next to a substance that is almost never what it is sold as, would be actively harmful. What can be said without a number: the difference between a threshold experience and an overwhelming one is small, and nobody buying an illicit powder knows which they have.

As with all classic hallucinogens, the experience is heavily shaped by dose, by the individual, and by setting.

Source: DEA drug fact sheet; EUDA; PubChem CID 98527

Risks & harms

The dominant risk is not the pharmacology of 2C-B. It is that the substance is usually something else. On the Energy Control figures above, a person buying “2C-B” on an illicit market is far more likely to receive a ketamine and MDMA mixture of unknown proportions than the compound they asked for. Every risk that follows from ketamine, from MDMA, and from combining them therefore applies to a purchase of 2C-B, and the buyer has no way to know the ratio or the dose.

Where the compound genuinely is 2C-B, reported harms include acute anxiety and panic, nausea and vomiting, cardiovascular strain, and confusion or disorientation. Interactions are a serious and under-appreciated hazard: combining a serotonergic psychedelic with MDMA, with stimulants, or with an MAOI or serotonergic antidepressant carries a risk of serotonin toxicity, and a mixture sold as tusi may contain a serotonergic drug the person did not know they were taking.

Classic hallucinogens are generally considered to have low physical-dependence potential. That says nothing about the safety of a single acute reaction, and it says nothing at all about an unidentified mixture.

Because illicit supply has no quality control, dose is unknown, purity is unknown and identity is unknown. Drug-checking, where it is available, is the only thing that narrows any of those three.

Source: Abukahok N, Fitzgerald ND, Palamar JJ, Current Addiction Reports 2025;12:90; DEA drug fact sheet; EUDA

Subjective effects

dose-dependent serotonergic; low dose relaxed/heightened senses/euphoria; medium stimulant + full intoxication; high LSD-like hallucinations + morbid delusions

Onset

20–30 min

Peak

1.5–2 hr

Duration

up to 8 hr

Harmful effects

high-dose hallucinations/morbid delusions; persistent psychosis after single tablet; sold misrepresented as MDMA/LSD

Medicinal use

none in US; historical pre-1995 Shulgin psychotherapy use

History

synthesized 1974 by Alexander Shulgin from 2,5-dimethoxybenzaldehyde; pub. w/ Carter 1975; PiHKAL "warm hug"; sold as Nexus/Erox pre-scheduling; first DEA lab ID 1986

Prevalence

NFLIS >1,500 reports since 1998; peak 201 (2019), 76 (2024)

Images

Visual references coming soon.

If it’s too intense

If an experience becomes overwhelming, the goal is to stay safe and let it pass, most difficult experiences ease as the drug wears off.

  • Get to a calm, safe space with someone you trust who is sober and can stay with you.
  • Cool down if you’re overheating, move somewhere cool, remove extra layers, rest. Overheating is especially a risk with stimulants and MDMA.
  • Sip water to thirst, but don’t over-hydrate. Drinking large amounts of plain water (especially after MDMA) can dangerously dilute your blood sodium (hyponatremia). Electrolytes help more than volume.
  • Slow your breathing, long, slow exhales help settle a racing heart and anxiety.
  • A sugary drink, fruit juice, or a snack can ease shakiness and the anxiety that comes with low blood sugar.
  • Do not take more, and do not add another substance to manage it. Redosing or adding something else (including a sedative like a benzodiazepine) can make things worse, not better.

With psychedelics, fear and confusion are usually temporary. Change your surroundings, calmer light, quiet music, a trusted person, and remind yourself it will lift as the drug wears off.

Call 911 (or Poison Control, 1-800-222-1222) right away for chest pain, a very high body temperature, a seizure, unconsciousness, or severe confusion. These are medical emergencies, not something to wait out.

Source: general harm-reduction guidance from SAMHSA, NIH/NIDA, and MedlinePlus, in our own words. Draft, not yet medically reviewed.

Forensic dossier

Draft · every field is source-cited or marked “Unknown, pending review”

Identity

IUPAC name
2-(4-bromo-2,5-dimethoxyphenyl)ethanaminePubChem PUG-REST ↗ · retrieved 2026-06-18
SMILES
COC1=CC(=C(C=C1CCN)OC)BrPubChem PUG-REST ↗ · retrieved 2026-06-18
InChIKey
YMHOBZXQZVXHBM-UHFFFAOYSA-NPubChem PUG-REST ↗ · retrieved 2026-06-18
Synonyms / aliases
nexus, bromo, Nexus, BDMPEA, 2-CB, Nexus (pharmaceutical), DEA No. 7392, .ALPHA.-DESMETHYL DOB, YMHOBZXQZVXHBM-UHFFFAOYSA-N, MFTPubChem PUG-REST + seed aliases ↗ · retrieved 2026-06-18

Composition

Composition
N/A — single compound (see Identity)

Physical / pill characteristics

Dosage form
Unknown — pending review (no Rx/OTC label; illicit — pill visuals = FIRST-PARTY submissions only, never generated or scraped)
Route
Unknown — pending review
Shape
Unknown — pending review
Color
Unknown — pending review
Imprint
Unknown — pending review
Score
Unknown — pending review

Scheduling & legal status

International
Unknown, pending review

Effects, risks & interactions

Effects
2C-B is a psychedelic phenethylamine that produces dose-dependent changes in perception, mood and sensory experience — users commonly report visual and tactile distortion, altered sense of time, heightened sensory awareness and euphoria, with a stimulant character that distinguishes it from classic tryptamine psychedelics. Onset and duration vary with the individual and the (unverifiable, illicit) amount taken.NIDA + MedlinePlus ↗ · retrieved 2026-06-18
Risks
Reported adverse effects include nausea, anxiety or agitation, confusion, and raised heart rate and blood pressure; higher exposure can produce distressing or disorienting experiences. A central harm-reduction concern is mis-selling: powders sold as "2C-B" — especially "pink cocaine"/tusi — frequently contain little or no 2C-B (see the tusi dossier), so buyers cannot know the actual contents without drug-checking.NIDA + MedlinePlus ↗ · retrieved 2026-06-18
Interactions
Unknown, pending review

Dosage

Pending medical reviewer

Sources

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